GPT-5.3-Codex-Spark vs Grok 3 Mini
GPT-5.3-Codex-Spark (2026) and Grok 3 Mini (2025) are agentic coding models from OpenAI and xAI. GPT-5.3-Codex-Spark ships a 131K-token context window, while Grok 3 Mini ships a 131k-token context window. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit. It focuses on practical selection signals rather than broad model-family marketing. The goal is to make the tradeoff clear before deeper testing.
GPT-5.3-Codex-Spark is safer overall; choose Grok 3 Mini when provider fit matters.
Decision scorecard
Local evidence first| Signal | GPT-5.3-Codex-Spark | Grok 3 Mini |
|---|---|---|
| Decision fit | Coding, RAG, and Agents | RAG, Long context, and Vision |
| Context window | 131K | 131k |
| Cheapest output | - | $1.27/1M tokens |
| Provider routes | 1 tracked | 2 tracked |
| Shared benchmarks | 0 rows | 0 rows |
Decision tradeoffs
- GPT-5.3-Codex-Spark has the larger context window for long prompts, retrieval packs, or transcript analysis.
- GPT-5.3-Codex-Spark uniquely exposes Function calling, Tool use, and Code execution in local model data.
- Local decision data tags GPT-5.3-Codex-Spark for Coding, RAG, and Agents.
- Grok 3 Mini has broader tracked provider coverage for fallback and procurement flexibility.
- Grok 3 Mini uniquely exposes Multimodal in local model data.
- Local decision data tags Grok 3 Mini for RAG, Long context, and Vision.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output prices on this page.
GPT-5.3-Codex-Spark
Unavailable
No complete token price in local provider data
Grok 3 Mini
$518
Cheapest tracked route: Microsoft Foundry
Cost delta unavailable until both models have sourced input and output token prices.
Switch friction
- No overlapping tracked provider route is sourced for GPT-5.3-Codex-Spark and Grok 3 Mini; plan for SDK, billing, or endpoint changes.
- Check replacement coverage for Function calling, Tool use, and Code execution before moving production traffic.
- Grok 3 Mini adds Multimodal in local capability data.
- No overlapping tracked provider route is sourced for Grok 3 Mini and GPT-5.3-Codex-Spark; plan for SDK, billing, or endpoint changes.
- Check replacement coverage for Multimodal before moving production traffic.
- GPT-5.3-Codex-Spark adds Function calling, Tool use, and Code execution in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-02-12 | 2025-02-17 |
| Context window | 131K | 131k |
| Parameters | — | — |
| Architecture | decoder only | - |
| License | Proprietary | Proprietary |
| Knowledge cutoff | - | 2024-11 |
Pricing and availability
| Pricing attribute | GPT-5.3-Codex-Spark | Grok 3 Mini |
|---|---|---|
| Input price | - | $0.25/1M tokens |
| Output price | - | $1.27/1M tokens |
| Providers |
Capabilities
| Capability | GPT-5.3-Codex-Spark | Grok 3 Mini |
|---|---|---|
| Vision | No | No |
| Multimodal | No | Yes |
| Reasoning | No | No |
| Function calling | Yes | No |
| Tool use | Yes | No |
| Structured outputs | Yes | Yes |
| Code execution | Yes | No |
Benchmarks
No shared benchmark rows are currently sourced for this pair.
Deep dive
The capability footprint differs most on multimodal input: Grok 3 Mini, function calling: GPT-5.3-Codex-Spark, tool use: GPT-5.3-Codex-Spark, and code execution: GPT-5.3-Codex-Spark. Both models share structured outputs, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.
Pricing coverage is uneven: GPT-5.3-Codex-Spark has no token price sourced yet and Grok 3 Mini has $0.25/1M input tokens. Provider availability is 1 tracked routes versus 2. Treat unknown pricing as an integration gap, then verify the route you will actually call before estimating production spend.
Choose GPT-5.3-Codex-Spark when coding workflow support and larger context windows are central to the workload. Choose Grok 3 Mini when provider fit and broader provider choice are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship. This keeps the decision grounded in measurable tradeoffs instead of brand-level assumptions. It also helps separate model capability from provider packaging, which can change cost and latency. For teams standardizing a stack, that distinction is often the difference between a benchmark win and a reliable deployment.
FAQ
Which has a larger context window, GPT-5.3-Codex-Spark or Grok 3 Mini?
GPT-5.3-Codex-Spark supports 131K tokens, while Grok 3 Mini supports 131k tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Is GPT-5.3-Codex-Spark or Grok 3 Mini open source?
GPT-5.3-Codex-Spark is listed under Proprietary. Grok 3 Mini is listed under Proprietary. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Which is better for multimodal input, GPT-5.3-Codex-Spark or Grok 3 Mini?
Grok 3 Mini has the clearer documented multimodal input signal in this comparison. If multimodal input is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Which is better for function calling, GPT-5.3-Codex-Spark or Grok 3 Mini?
GPT-5.3-Codex-Spark has the clearer documented function calling signal in this comparison. If function calling is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Which is better for tool use, GPT-5.3-Codex-Spark or Grok 3 Mini?
GPT-5.3-Codex-Spark has the clearer documented tool use signal in this comparison. If tool use is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run GPT-5.3-Codex-Spark and Grok 3 Mini?
GPT-5.3-Codex-Spark is available on OpenAI API. Grok 3 Mini is available on OpenRouter and Microsoft Foundry. Provider coverage can affect latency, region availability, compliance posture, and fallback options. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
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Last reviewed: 2026-05-19. Data sourced from public model cards and provider documentation.